Pat,
I run around a 20:30 as well and do speedwork around 2x a month though I try to do it 1x a week (life gets in the way). Anyway, my ideal schedule is as follows:
Sunday 7 - 10 miles @ 9:00, Monday - Off, Tuesday 3-4 miles @ 8:30 - 9, Wednesday 4-5 miles @ 8:30 - 9, Thursday - track...